Time switch



Jun; 24, 1924. I 1,498,573

'8. H. POMEROY TIME SWITCH Filed Feb. 18 1922 Bevmard H. Pomero IN VENTOR.

Patented June 24, 1924.

UNITED STATES BENNARD H. POMEROY, OF ROCHESTER, YORK.

TIME SWITCH.

Application filed February 18, 1922. Serial No. 537,623.

- T all whom it may concern:

Be it known that I, BENNARD H. PoMuaor, a citizen of the United Statesof America, residing at Rochester, in the county of Monroe and State ofNew York, have invented certain new and useful Improvements in TimeSwitches, of which the following is a specification.

The object of this invention is to provide an electrical switch for usein connection with heating devices designed to furnish heat for alimited time only. Such heaters are employed in manifolds and operate togasify the gasoline and air mixture drawn through the carburetor of aninternal combustion engine.

These and other objects of this invention will be fully illustrated inthe drawing described in the specification and pointed out in the claimsat the end thereof.

In the accompanying drawing:

Figure 1 is a vertical sectional view of the switch as it will appearwhen attached to the dash board of an automobile.

Figure 2 is a top plan view of the switch.

Figure 3 is abottom plan view ofthe switch.

Figure 4c is an end elevation of the switch.

Figure 5 is a vertical sectional view of the switch, the section beingtaken on the line 5*5" of Figure 2.

Figure 6 is a vertical section of the switch. the section being taken onthe line 6 6 of Figure 3.

In the several figures of the drawing like reference numerals indicatelike parts.

Electric manifold heaters such as are in tended to be controlled by theswitch forming the subject matter of this invention comprise a heatingcoil which is mounted in the manifold of an internal combustion engineso that the gases passing into the intake of the engine are preheatedand vaporized thereby before entering the cylinders. The coil of theseheaters is brought to a high degree of temperature by an electriccurrent which in the case of an automobile is furnished by the storagebattery of the lighting or ignition system of the car. As a large amountof current is drawn by the heater from thebattery during the time theheater is in use it is imperative that the time during which the heateris in use be limited to the actual time necessary to gasify sufficientfuel to run the engine until the heat of the engine itself will operateto gasify the fuel without the use of the heater. This is needed toavoid waste of current and protect the battery against exhaustion.

This time limit may be set for a minute or a fraction of a minutedepending on the climate and to a certain extent the type of englue.

The switch proper comprises the face plate 1 in which the push button 2is mounted. To provide a limited movement for the push button 2 in theface plate 1 the face plate is bulged out in the middle to form aclearance 3 between the face plate. A. collar 5 is formed at the rear ofthe push button to limit the movement thereof in either direction bymaking contact with face plate at one end and with the backing plate atthe other end of its movement.

The push button is provided with an extension 6 of reduced diameterwhich extends rearwardly through an opening in the backing plate intothe sleeve 7 formed integral with the backing plate or suitably fastenedthereto. The front half of the sleeve as well as the opening in thebacking plate has an inside diameter which is slightly larger than theoutside diameter of the extension 6 of the push button. Placed into theclearance formed in the sleeve 7 in this manner is the expansion spring8 which encircles the em tension 6 of the push button and is held inplace between the rear of the collar 5 and the shoulder 9 formed at theend of the enlarged section of the sleeve. The spring 8 normally forcesthe push button outwardly into the full line positionillustrated inFigure 1.

Mounted on the outer end of the sleeve 7 is a disk or plate 10. On thisplate are car ried the posts 11 and 12 which project rearwardlytherefrom preferably at diagonal points from each other. These postssupport a second disk or plate 13 at a suitable distance from the firstplate 10. lVhile the first plate is made of metal and forms a goodconductor of electricity the second plate 13 is made of insulatingmaterial such as fiber and forms the switch board proper.

The switch mounted on the insulating disk 13 is a knife switch andcomprises the blade 14 and the clip 15. The blade 14 is pivotallymounted on the lug 16 near the bottom of the insulating disk and theclip 15 is mounted near the top of the same disk. A spring 17 is held inplace on the lug 16 and the free end thereof is wound around the lowerend of the knife blade 1& and normally holds the upper end thereof outof engagement With the clip 15. In doing so the rear of the blade 1 1 isforced against the opening in the front of the plate 10 forming acontinua-tion of the sleeve 7 The end of the extension 6 of the pushbutton 2 is adapted to move out of this opening in the plate when thepush button is operated and makes con- 7 tact with and swings the blade14 into engagement with the clip 15. The frictional contact which theend of the blade makes with the clip'is sufficient to hold the blade inengagement with the clip against the force of the action of the spring17 so that on the release of the push but-ton by the operator the knifeswitch remains closed while the push button is forced back from thedotted line position which the push button occupies when operating theswitch as above pointed out to the full line or normal position. This isautomatically done by the action of the expansion spring 8 onthe releaseof the push button.

The electric current passes through the switch when closed as follows.It enters through the wire marked 18 which is suitably connected to theclip 15. From the clip the current passes through the knife blade 1a tothe lug 16 on which the blade is mounted to swing. This lug in turn isconnected to the heating coil 20 wound around a portion of thethermometal spring 21. The wire in this heating coil is copper and ispreferably uninsulated. From this coil the current passes to one of theposts 11 or 12 from either one of which it passes to the heater in themanifold such as is described in my prior application 390,625 filed June21, 1920, which is cont-rolled by the operation of .the switchl 1 Thethermometal spring is mounted with 7 one end thereof to the under sideof the .does not make contact with it.

sleeve 7 near the backing plate thereof and its outer end is left toproject into the path of the lug 22 formed on the rear of the blade 14of the switch proper. While the switch is open and no current passestherethrough following the path outlined above the lug 22 on the bladeis located slightly below the outer end of the thermometal spring andWVhen the switch is closed the lug 22 is forced against the under sideof the t-hermometal spring 21 and slightly raises the outer end thereofwhile it makes contact therewith. As soon as the. circuit is closed theelectric current passes through the heating coil 20 following the pathabove pointed out and heats the coil 20 and in turn the thermomet-alspring, '21.

Th'erm'ometal which is used in making the spring-21is made up of twometals each having a different coeflicient of expansion,

of the sheet, with the consequence that the metal having the greaterexpansion must expand by curving around the metal having the smallerexpansion, as neither one can separate itself from the other to expandin a straight line independently. 1

When, therefore, the therinonietal spring 21 employed in this switch isheated by the heating coil 20the outer end thereof curves during itsexpansion and this action of the thermometal spring operates to forcedown on the lug 22 and pull the knife blade 1 1 out of engagement withthe clip 15. The electric circuit is thus automatically broken by theexpansion of the thermome'tal spring caused by the application of heatthrough the electric current which passes through the switch.

The knife blade 14 has a vertical groove 23 cut into one side thereofnear the outer end of the blade. The clip 15 has an inwardly projectingridge 2 f formed near the outer end of one of the jaws of the clip onthe same side on which the groove 23 is provided in the knife blade. Theridge 24c of the clip 15 is adapted to make frictional contact with theside of the-knife blade on which the groove 23 is formed and to enterthis groove to hold the knifeblade in engagement with the clip to closethe electric circuit. 7

The distance between'the aws of the 'clip 15 is so adjusted that whenthe knife blade enters between them to close the electric circuit it isheld yieldingly in frictional engagement between them by reason oftheengagement of the ridge 24 with the groove 23; The amount of pressureneeded to pull the knife blade out of engagement with the clipdetermines the time that it takesthe'thermometal spring to perform thisoperation. This is regulated by increasing or decreasing the distancebetween the iawsof the clip 15 so that the knife blade is held in theclip with stronger or weaker grip, which in turn allows the thermometalspring to pull the knife blade outof engagement with'the clip ina longeror shorter period from the time the switch is :closed to close theelectric circuit. p

The manifold heating coil in connection with which the switch is used isheatedbe ,fore'the engine starts'and being located in the manifold itheats the mixture. in the it will on its first turn draw a hot chargeinto the engine which is easily fired and starts the cycle of theengine. The application of the current to the coil for thirty to sixtyseconds before starting the engine is usually sufficient on a coldmorning to secure this result, and the switch shown in the drawing isset to operate to break the circuit in this length of time after the circuit has been closed by operating the push button. I

The face plate may be conveniently fastened to the dashboard of anautomobile at a point where the operator of the car can readily reachthe push button.

For the purpose of manually breaking the switch in the event that thethermometal spring fails to perform its function, a dog 25 is providedon the end of the extension of the push button. This dog is fastened toone side of the end of the extension and normally does not make contactwith the knife blade during its forward and rearward movement with thepush button. Should the knife blade fail to disengage itself from theclip, the push button, with the help of the dog 25, can be used to openthe switch. For this purpose the push button is pushed in until the endof its extension is brought into contact with the back of the knifeblade 14:. The push button is then turned until the hook shaped end ofthe dog engages the front of the knife blade, as illustrated in Fig. 6.When this is done the push button is released and the expansion of thespring 8 brings the push button back to its normal position. In doing sothe knife blade which has been hooked by the dog 25 is pulled back withthe push button and out of engagement with the clip 15. When the switchhas been opened in this way the push button may be turned back to itsnormal position to disengage the dog 25 from the knife blade, so that onthe next operation of the push button the switch does not open when thebutton is released by the operator.

This invention is described in connection with a heating coil but itwill be understood that it can be used effectively for many otherpurposes as Well.

I claim:

1. In a thermostatically controlled time switch the combination of apush button, a knife switch, said push button being adapted to closesaid knife switch, a thermometal spring adapted to open said knifeswitch and a heating coil surrounding said thermometal spring andelectrically connected in series with said knife switch and means foropening said knife switch independently of said thermometal spring.

2. In a thermostatically controlled time switch, the combination of apush button, a sleeve surrounding said push button, a plate supported onthe end of said sleeve, a. pair of posts projecting rearwardly from saidplate, an insulating panel supported by said posts, a knife switchmounted on said insulating panel, a thermometal spring mounted on saidsleeve, said push button being .mounted on said plate diametricallyopposite to said clip, said push button being adapted to engage the rearof said knife blade and operate to move said blade into engagement withsaid clip, a thermometal spring adapted to pull said knife blade out ofengagement with said clip, a heating coil electrically connected inseries with said knife blade to raise the temperature of saidthermometal spring and pull the knife blade out of engagement with saidclip to break the electric circuit formed by said knife switch on theoperation of said push button.

4;. In a thermostatically controlled time switch, the combination of asleeve, a push button mounted to slide in said sleeve, a knife switchcomprising a knife blade mounted to swing on the end of said sleeve, aclip adapted to receive the end of said knife blade, said push buttonadapted to engage said knife blade and force it into engagement withsaid clip, a thermometal spring, a lug projecting rearwardly on saidknife blade, said thermometal spring being adapted to engage said lugwhen said switch is closed and pull said knife blade out of said clip toopen the circuit.

5. In a thermostatically controlled electric switch the combination of aknife switch, comprising a knife blade and a clip, a thermometal springoperating on said knife blade to open the knife switch at apredetermined period after closing the switch, manual means operating toclose said switch and means carried on said manually operated means toeither leave the knife blade in engagement with the clip or withdrawtherefrom on the release of said manually operated means.

6. In a thermostatically controlled electric switch the combination of aknife switch comprising a knife blade and a. clip, a thermometal springoperating on said knife blade to open the knife switch at apredetermined period after closing the switch, a push button operatingto close said switch, a dog carried on said push button and moving backand forth and turning sideways therewith, said dog when turned to oneposition being adapted to engage the knife blade to open the switch onthe backward movement of said button, and when in normal angularposition being adapted to leave the switch ilosed on the backwardmovement of said button. v

7. In a thermostatically controlled switch 3 the combination of a knifeswitch comprising a knife blade and a clip intowhich said knife bladeengages, a push button adapted to engage the rear of said knife bladeand to force said knife blade in engagement with .9 said clip on-theforward movement thereof,

